Cooling device and electronic device including the same

ABSTRACT

A cooling device includes: a heat sink including a plurality of fins formed to be plate shaped, which are arranged in parallel to one another; and a cooling fan arranged in a direction from the heat sink, the direction being perpendicular to perpendicular lines of the fins. A plurality of fins of a side heat sink constituting the heat sink include edges aligned on an oblique line with respect to perpendicular lines of the fins and formed on the outer periphery of the cooling fan. With this structure, it is possible to improve usage efficiency of an air flow generated by the cooling fan.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority from Japanese application JP2010-061704 filed on Mar. 17, 2010, the content of which is hereby incorporated by reference into this application.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a cooling device for cooling an electronic component mounted on a circuit board, and more particularly, to a technology for increasing usage efficiency of an air flow generated by a cooling fan.

2. Description of the Related Art

There is known an electronic device (for example, personal computer, game device, or audio-visual device) including a cooling device for cooling an electronic component mounted on a circuit board (see U.S. Pat. No. 6,637,505). There is known a cooling device including a heat sink for receiving heat from an electronic component, and a cooling fan for generating an air flow that passes through the heat sink. Further, there is known a heat sink including a plurality of fins with plate shapes, which are aligned at intervals in a lateral direction.

SUMMARY OF THE INVENTION

In the cooling device, in some cases, the cooling fan is arranged so that the center line of rotation is directed upward, and the cooling fan in such a posture is arranged in front of the heat sink including the fins aligned in the lateral direction. In this layout, even though air to flow to a radially outer side of the cooling fan is generated by driving of the cooling fan, only air flowing substantially just rearward from the cooling fan to the heat sink is used for cooling the electronic component. Thus, usage efficiency of the air flow is not satisfactory.

A cooling device according to the present invention includes: a heat sink including a plurality of fins formed to be plate shaped and aligned at intervals, the heat sink being arranged such that perpendicular line of any one of the plurality of fins are along a first direction; and a cooling fan situated from the plurality of fins in a second direction perpendicular to the first direction, the cooling fan being rotatable about a center line along a third direction perpendicular to both the first direction and the second direction. The heat sink includes a plurality of oblique arrangement fins serving as at least one part of the plurality of fins. The plurality of oblique arrangement fins include edges aligned on an oblique line with respect to the first direction and formed on an outer periphery of the cooling fan.

An electronic device according to the present invention includes the cooling device.

According to the present invention, the edges of the plurality of oblique arrangement fins are aligned on the oblique line with respect to the first direction which is defined as a direction along the perpendicular line of the fin, and formed on the outer periphery of the cooling fan. Thus, the air flowing from the cooling fan obliquely with respect to the second direction can pass through the heat sink, and hence it is possible to increase the usage efficiency of the air flow.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is a perspective view of an electronic device defining an example of an embodiment of the present invention;

FIG. 2 is a plan view of the electronic device from which an upper housing is removed;

FIG. 3 is a sectional view taken along the line III-III of FIG. 2;

FIG. 4 is a plan view of a cooling device of the electronic device;

FIG. 5 is an exploded perspective view of the cooling device;

FIG. 6 is a plan view of a heat sink of the cooling device;

FIG. 7 is a bottom view of the cooling device;

FIG. 8 is a sectional view taken along the line VIII-VIII of FIG. 6;

FIG. 9 is a sectional view taken along the line IX-IX of FIG. 6; and

FIG. 10 is an enlarged view of a main part of FIG. 6.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, an embodiment of the present invention is described with reference to the drawings. FIG. 1 is a perspective view of an electronic device 1 defining an example of the embodiment of the present invention. FIG. 2 is a plan view of the electronic device 1 from which an upper housing 22 is removed. FIG. 3 is a sectional view taken along the line III-III of FIG. 2. FIG. 4 is a plan view of a cooling device 10 of the electronic device 1. FIG. 5 is an exploded perspective view of the cooling device 10. FIG. 6 is a plan view of a heat sink 11 of the cooling device 10. FIG. 7 is a bottom view of the cooling device 10. FIG. 8 is a sectional view taken along the line VIII-VIII of FIG. 6, and FIG. 9 is a sectional view taken along the line IX-IX of FIG. 6. FIG. 10 is an enlarged view of a main part of FIG. 6. Note that, in those drawings, the arrow Y1 indicates a rear direction, and the arrow Y2 indicates a front direction. Further, the arrow X1 indicates a right direction, and the arrow X2 indicates a left direction.

As illustrated in FIG. 1, the electronic device 1 includes a housing 2. The housing 2 includes a box-shaped lower housing 21 opened upward, and a box-shaped upper housing 22 opened downward, for covering the upper side of the lower housing 21. The upper housing 22 includes an upper panel portion 22 a situated over various devices built in the electronic device 1. The upper panel portion 22 a is curved so that its center portion in a fore-and-aft direction (Y2-Y1 direction) swells upward. That is, the rear portion of the upper panel portion 22 a is formed to extend downward toward the rear side, and the front portion of the upper panel portion 22 a is formed to extend downward toward the front side.

The upper housing 22 includes a right front wall portion 22 b and a left front wall portion 22 c, each of which extends downward from a front edge of the upper panel portion 22 a toward the lower housing 21. The electronic device 1 is an entertainment device such as a game device and an audio-visual device that reads data and a program stored in a hard disk device, a disc-shaped portable storage medium such as an optical disc, and the like, and provides moving image, and sounds to a user. An insertion slot 22 d, through which such a storage medium is inserted, is formed in the right front wall portion 22 b. The right front wall portion 22 b is situated more rearward than the left front wall portion 22 c. A front board 22 e extending forward from a lower edge of the right front wall portion 22 b is arranged in front of the right front wall portion 22 b. The front board 22 e is provided with a plurality of buttons 23 functioning as an eject button for ejecting a storage medium, a power button, and the like.

As illustrated in FIG. 2 or FIG. 3, the electronic device 1 includes: a power source unit 3 for converting electric power supplied from the outside of the electronic device 1 into electric power for driving each device built in the electronic device 1; a reading device 4 for reading data and the like stored in a storage medium inserted through the insertion slot 22 d; a circuit board 5 on which integrated circuits 5A, 5B are mounted, the integrated circuits performing processing such as generating moving images based on the read data and the like; and the cooling device 10 for cooling the integrated circuits 5A, 5B. In this example, the two integrated circuits 5A, 5B aligned in the fore-and-aft direction are mounted on the circuit board 5.

The power source unit 3 includes a circuit board 32 on which a power circuit is mounted, and a case 31 housing the board 32. The case 31 in this example has a substantially rectangular parallelepiped shape elongated in a right-and-left direction. The width of the case 31 in the right-and-left direction ranges from one side surface to the opposite side surface of the electronic device 1. As illustrated in FIG. 3, a front wall 31 c of the case 31 has air inlets 31 a formed therein, through which the air from the cooling device 10 flows. Further, a rear wall 31 d of the case 31 has air outlets 31 b formed therein, through which the air inside the case 31 is discharged to the outside. In this example, the air outlets 31 b are provided in an entire area of the rear wall 31 d. That is, the area where the air outlets 31 b are formed ranges from a left end to a right end of the rear wall 31 d. In this example, the case 31 is arranged in the rear portion of the electronic device 1. Further, an opening is formed in a rear wall of a housing 2. The rear wall 31 d of the case 31 is exposed to the rear side through the opening. Therefore, at the time when the air inside the case 31 is discharged through the air outlets 31 b, the air is simultaneously discharged from the housing 2.

The cooling device 10 and the reading device 4 are arranged in front of the power source unit 3, and are aligned side by side. The circuit board 5 is arranged on lower sides of the cooling device 10 and the reading device 4.

As illustrated in FIG. 3 or FIG. 5, the cooling device 10 includes the heat sink 11 for receiving heat from the integrated circuits 5A, 5B, and a cooling fan 15 for generating an air flow that passes through the heat sink 11. Further, the cooling device 10 includes a base plate 18 on which the heat sink 11 is arranged, and a cover 19 covering the upper side of the heat sink 11.

As illustrated in FIG. 3 or FIG. 5, the heat sink 11 includes a plurality of fins 12 a, 13 a, and 14 a that are arranged in parallel to one another and aligned at intervals. Each of the fins 12 a, 13 a, and 14 a is formed into a quadrangular plate shape. As illustrated in FIG. 6, the cooling fan 15 is arranged in a direction from the heat sink 11, which is defined as a direction perpendicular to a direction along perpendicular lines of the fins 12 a, 13 a, and 14 a (direction perpendicular to surfaces of the fins). In other words, a direction in which the heat sink 11 and the cooling fan 15 are aligned is perpendicular to the perpendicular lines of the fins 12 a, 13 a, and 14 a. Said in another way, the direction in which the heat sink 11 and the cooling fan 15 are aligned with each other is parallel to the fins 12 a, 13 a, and 14 a, that is, parallel to the surfaces of the fins 12 a, 13 a, and 14 a. In this example, the cooling fan 15 is arranged in front of the heat sink 11. Further, in this example, the above-mentioned direction along the perpendicular lines of the fins 12 a, 13 a, and 14 a is defined as the right-and-left direction. Hereinbelow, the above-mentioned direction of the perpendicular lines is simply referred to as the right-and-left direction. Further, a direction perpendicular to the above-mentioned direction along the perpendicular lines is defined as the fore-and-aft direction, and hereinbelow, the perpendicular direction is simply referred to as the fore-and-aft direction. The cooling fan 15 is arranged so that a center line C thereof is along a direction (in this example, up-and-down direction) perpendicular to both the right-and-left direction and the fore-and-aft direction. In other words, the center line C is directed to a direction in which the fins 12 a, 13 a, and 14 a are upright. The cooling fan 15 is rotatable about the center line C. That is, the cooling fan 15 includes a plurality of fins 15 b extending radially outward. Driving of a motor of the cooling fan 15 rotates the fins 15 b about the center line C. When the cooling fan 15 is rotated, the air over and under the cooling fan 15 is introduced into the cooling fan 15. Then, the air is sent out to a radially outer side of the cooling fan 15 and then passes through the heat sink 11. That is, the cooling fan 15 is arranged on an upstream side of the heat sink 11 in a path of the air flow.

As illustrated in FIG. 4 or FIG. 5, the cover 19 includes an upper panel portion 19 a which is situated over the heat sink 11, and a side wall portion 19 b which is upright on the base plate 18 and surrounds the cooling fan 15 and the heat sink 11. An opening 19 f is formed in the upper panel portion 19 a. The cooling fan 15 is fitted into the opening 19 f, and is fixed onto the cover 19. Specifically, the cooling fan 15 includes a circular fitting plate 15 c in the upper portion thereof. The fitting plate 15 c includes two fitting portions 15 d protruding radially outward. An edge of the fitting plate 15 c is placed on an edge of the opening 19 f. The fitting portions 15 d are fixed, with screws, bolts, or the like, to fitting portions 19 g provided in the edge of the opening 19 f. In this regard, an annular hole 15 e is formed in the fitting plate 15 c, and the air above the cooling fan 15 is introduced through the hole 15 e. Further, as illustrated in FIG. 3, an opening 18 c situated under the cooling fan 15 is formed in the base plate 18. The air below the cooling fan 15 is introduced through the opening 18 c into the cooling fan 15.

As described above, the side wall portion 19 b is formed to surround an outer periphery of the cooling fan 15 and side surfaces of the heat sink 11. As illustrated in FIG. 4 or FIG. 5, the side wall portion 19 b in this example includes a curved wall portion 19 c, a left wall portion 19 d, and a right wall portion 19 e that are continuous with one another. The curved wall portion 19 c is curved along the outer periphery of the cooling fan 15 (the outer periphery is defined as a track formed by edges of tip ends of the fins 15 b when the cooling fan 15 is rotated), to thereby surround the cooling fan 15. The left wall portion 19 d is upright on a left side of the heat sink 11, and the right wall portion 19 e is upright on a right side of the heat sink 11. Further, the curved wall portion 19 c includes a distant curved wall portion 19 h. The distant curved wall portion 19 h defines a section of the curved wall portion 19 c which close to the left wall portion 19 d. A distance between the outer periphery of the cooling fan 15 and the distant curved wall portion 19 h is increased toward the left wall portion 19 d. Thus, the distant curved wall portion 19 h and the cooling fan 15 have an air passage therebetween which is gradually increased in size as approaching to the heat sink 11.

As illustrated in FIG. 5, an opening 19 i opened rearward is formed in the cover 19. The air flow generated by rotation of the cooling fan 15 passes through the heat sink 11, and is discharged rearward through the opening 19 i. As described above, the power source unit 3 is arranged behind the cooling device 10. As illustrated in FIG. 3, the front wall (wall facing to the opening 19 i) of the case 31 of the power source unit 3 has the air inlets 31 a formed therein. Further, the rear wall of the case 31 has the air outlets 31 b formed therein. The air, which is discharged through the opening 19 i of the cover 19, flows through the air inlets 31 a into the case 31. Then, after passing through between various electronic components mounted on the board 32 housed in the case 31, and then cooling the same, the air is discharged through the air outlets 31 b to the outside. In this regard, a device to be arranged behind the cooling device 10 is not limited to the power source unit 3, and another device (for example, hard disk device, another circuit board on which the integrated circuit is mounted, etc.) built in the electronic device 1 may be arranged.

As illustrated in FIG. 5 or FIG. 6, the heat sink 11 illustrated in this example includes a front heat sink 12, a rear heat sink 13, and a side heat sink 14. The front heat sink 12 and the rear heat sink 13 are arranged side by side in the fore-and-aft direction. The side heat sink 14 is situated in one of the right direction and the left direction (in this example, left direction) from the front heat sink 12 and the rear heat sink 13. In this example, the front heat sink 12, the side heat sink 14, and the rear heat sink 13 are individual parts. That is, the front heat sink 12, the side heat sink 14, and the rear heat sink 13 are independent heat sinks, and hence direct transfer of the heat among the heat sinks 12, 13, and 14 is restricted. The heat can be transferred from the front heat sink 12 to the side heat sink 14 through a heat pipe 42 described below.

As illustrated in FIG. 6, the front heat sink 12 and the rear heat sink 13 are situated behind the cooling fan 15. Specifically, the heat sinks 12, 13 are situated on a straight line L1 that passes through the center line C of the cooling fan 15 and is along the fore-and-aft direction. Meanwhile, the side heat sink 14 is offset to one side from the straight line L1. That is, all part of the side heat sink 14 is situated on the one side (in this case, left side) of the straight line L1. In this example, a center in the right-and-left direction of each of the front heat sink 12 and the rear heat sink 13 is offset in the right direction from the straight line L1.

The front heat sink 12 includes the plurality of fins 12 a which are arranged in parallel to one another and aligned at intervals. The fins 12 a are each formed into a plate shape facing toward the lateral sides, and are arranged in parallel to the straight line L1. The front heat sink 12 is substantially rectangular in plan view. Front edges 12 b of the plurality of fins 12 a are aligned on straight line L2, and rear edges 12 c of the plurality of fins 12 a are aligned on straight line L3. The straight lines L2 and L3 are perpendicular to the straight line L1 and are parallel to each other.

As illustrated in FIG. 8, the front heat sink 12 includes a plate-shaped base portion 12 d in the lower portion thereof. The respective fins 12 a are formed to be upright on the base portion 12 d. A plate-shaped heat receiving block 41 is fixed on the lower surface of the base portion 12 d. The heat receiving block 41 is fixed on the lower surface of the base portion 12 d by, for example, soldering. The heat receiving block 41 is pressed on the upper surface of the integrated circuit 5A mounted on the circuit board 5 (see FIG. 3). Thus, the heat of the integrated circuit 5A is transferred to the front heat sink 12 through the heat receiving block 41. In this regard, as illustrated in FIG. 7, a width in the fore-and-aft direction of the heat receiving block 41 is larger than a width in the fore-and-aft direction of the front heat sink 12. Therefore, a front edge 41 a of the heat receiving block 41 is situated further forward than a front edge of the base portion 12 d. In a portion of the heat receiving block 41 situated further forward than the base portion 12 d (hereinafter, referred to as front portion 41 b), the heat pipe 42 described below is arranged. Further, apart of the cooling fan 15 is situated over the front portion 41 b.

As illustrated in FIG. 8, the base plate 18 has an opening 18 a formed therein, which has a shape corresponding to a shape of the front heat sink 12, that is, a substantially rectangular shape. The base portion 12 d of the front heat sink 12 is fitted into the inside of the opening 18 a, and is fixed to the rear portion of the heat receiving block 41. The front portion 41 b of the heat receiving block 41 is fixed on the lower surface of the base plate 18.

As illustrated in FIG. 6, the rear heat sink 13 includes the plurality of fins 13 a, which are aligned at intervals. The fins 13 a are each formed into a plate shape facing toward the lateral sides, and are parallel to the straight line L1. Similarly to the front heat sink 12, the rear heat sink 13 is substantially rectangular in plan view. Similarly to the front edges 12 b and the rear edges 12 c of the fins 12 a, front edges 13 b and rear edges 13 c of the plurality of fins 13 a are aligned on straight lines which are perpendicular to the straight line L1 and are parallel to each other.

As illustrated in FIG. 6, in front of each of the fins 13 a of the rear heat sink 13, each of the fins 12 a of the front heat sink 12 is situated. That is, the fin 13 a and the fin 12 a situated in front of the fin 13 a are situated on a common plane. Thus, the air can smoothly pass through the front heat sink 12 and the rear heat sink 13.

In this regard, as illustrated in FIG. 6, the heat sink 11 is provided with a plurality of coupling pins 34, 35. The coupling pin 34 is stretched between the fin 12 a of the front heat sink 12 and the fin 13 a of the rear heat sink 13, to thereby establish electrical connection therebetween. Further, the coupling pin 35 is stretched between the fin 13 a of the rear heat sink 13 and the fin 14 a of the side heat sink 14, to thereby establish electrical connection therebetween. With this structure, each of the heat sinks 12, 13, and 14 can function also as a shielding member for suppressing electromagnetic interference of the electronic device 1.

As illustrated in FIG. 3, a height of the fin 13 a is larger than a height of the fin 12 a. Further, in accordance with the height difference between the fins 12 a and 13 a, a step 19 j is formed on the upper panel portion 19 a of the cover 19. With this structure, in the air passage from the cooling fan 15 to the power source unit 3, the cross-sectional size of the downstream of the passage (that is, rear heat sink 13) is larger than the cross-sectional size of the upstream of the passage (that is, front heat sink 12). Therefore, the air can smoothly flow from the front heat sink 12 to the rear heat sink 13.

As illustrated in FIG. 9, the rear heat sink 13 includes a plate-shaped base portion 13 d in the lower portion thereof. The respective fins 13 a are formed to be upright on the base portion 13 d. As illustrated in FIG. 3, the lower surface of the base portion 13 d is in contact with the upper surface of the integrated circuit 5B mounted on the circuit board 5. With this structure, the heat of the integrated circuit 5B is transferred to the rear heat sink 13.

As illustrated in FIG. 9, the base plate 18 has a plurality of elongated holes 18 b formed therein, which aligned in the right-and-left direction. The fins 13 a are fitted into the inside of the holes 18 b from below, respectively. Further, the position of the rear heat sink 13 is allowed to slightly change upward and downward with respect to the base plate 18. The positional change of the rear heat sink 13 can compensate height tolerance between the integrated circuit 5A and the integrated circuit 5B. That is, there is a case where the upper surface of the integrated circuit 5A is in close contact with the heat receiving block 41 fixed on the lower surface of the front heat sink 12, whereas a height of the upper surface of the integrated circuit 5B deviates from a normal height. Even in that case, owing to the positional change of the rear heat sink 13 in up-and-down direction the upper surface of the integrated circuit 5B and the lower surface of the rear heat sink 13 can be in close contact with each other.

As illustrated in FIG. 6 or FIG. 10, the side heat sink (first heat sink in claims) 14 includes the plurality of fins (oblique arrangement fins in claims) 14 a which are each formed into a plate shape facing toward the lateral sides. The plurality of fins 14 a are also arranged in parallel to one another, and are aligned at intervals. Similarly to the fins 12 a of the front heat sink 12 and the fins 13 a of the rear heat sink 13, each of the plurality of fins 14 a is also arranged in parallel to the straight line L1. Thus, the air, which passes through the respective heat sinks 12, 13, and 14, flows in the same direction (in this example, rearward).

The side heat sink 14 includes a plate-shaped base portion 14 d in the lower portion thereof (see FIG. 8). The respective fins 14 a are formed to be upright on the base portion 14 d. As described above, the side heat sink 14 is arranged next to the front heat sink 12 and the rear heat sink 13 (in this example, arranged on the left side thereof), and surrounds a part of the outer periphery of the cooling fan 15 together with the front heat sink 12 and the rear heat sink 13. A fin 14 a-2 situated at the end (right end) of the side heat sink 14 faces to a fin 12 a-1 situated at the end of the front heat sink 12, and a fin 13 a-1 situated at the end of the rear heat sink 13 (see FIG. 8 or FIG. 9).

As illustrated in FIG. 6 or FIG. 10, front edges (edges on the cooling fan sides in claim 14b of the fins 14 a are aligned on a line passing by the outer periphery of the cooling fan 15 (chain double-dashed line L4 of FIG. 10). Specifically, the front edges 14 b of the fins 14 a are aligned on a line L6 which extends obliquely with respect to the direction (in this example, right-and-left direction) along the perpendicular lines of the fins 12 a, 13 a, and 14 a, and formed on the outer periphery of the cooling fan 15. In this example, the line L6 extends forward and in the left direction. In other words, each of the fins 14 a is displaced forward from the adjacent fin 14 a. Positions of the front edges 14 b of the plurality of fins 14 a are shifted forward as their distances from the front heat sink 12 increase (in other words, as their distances from the straight line L1 increase). As a result, a front edge 14 b of a fin 14 a-1 situated at the end (in this case, left end) is situated further forward than a rearmost portion P1 of the outer periphery of the cooling fan 15. Further, the front edges 14 b of some of the fins 14 a are situated to the left of the rear portion of the cooling fan 15 (the rear portion is defined as a portion which is positioned further rearward than a straight line L8 that passes through the center line C and is parallel to the right-and-left direction). In this example, the front edges 14 b of most of the fins 14 a are situated to the left of the rear portion of the cooling fan 15, and are situated further forward than the rearmost portion P1 of the outer periphery of the cooling fan 15. In this regard, the front edge 14 b of the rightmost fin 14 a-2 is situated further rearward than the rearmost portion P1 of the outer periphery of the cooling fan 15.

The line L6, on which the front edges 14 b are aligned, is a straight line extending obliquely forward and leftward. The front edges 14 b of the plurality of fins 14 a are aligned in a direction parallel to a tangent line at a position different from the rearmost portion P1 of the outer periphery of the cooling fan 15 (in this case, position between the rearmost portion P1 and a leftmost portion P2 of the outer periphery of the cooling fan 15). Meanwhile, the front edges 12 b of the plurality of fins 12 a are aligned in a direction parallel to a tangent line at the rearmost portion P1 (that is, right-and-left direction). As illustrated in FIG. 6, the straight line L6 passes through an area surrounded by a straight line L7, a straight line L9 (straight line that passes through the leftmost portion P2 of the outer periphery of the cooling fan 15, and extends along the fore-and-aft direction), and the outer periphery of the cooling fan 15. In other words, the side heat sink 14 is arranged close to the cooling fan 15 so that the line L6, along which the front edges 14 b are aligned, passes through such area. In this regard, the line L6 is not limited to the straight line. For example, the line L6 may be curved in conformity with the outer periphery of the cooling fan 15.

As illustrated in FIG. 10, the side heat sink 14 illustrated in this example is a substantially parallelogram-shaped member in plan view. The plurality of fins 14 a are aligned in a direction oblique to the right-and-left direction (that is, direction parallel to the straight line L6), the respective fins 14 a facing toward the lateral sides. Accordingly, rear edges 14 c of the plurality of fins 14 a are aligned on the straight line L10 that is parallel to the straight line L6. In this regard, the shape of the side heat sink 14 is not limited thereto. For example, the side heat sink 14 may have a substantially trapezoid shape in plan view. In this case, the front edges 14 b of the fins 14 a are aligned on the straight line L6 that is oblique to the right-and-left direction, whereas the rear edges 14 c are aligned on, for example, the straight line that is parallel to the right-and-left direction. By forming the side heat sink 14 into a parallelogram or trapezoid shape in plan view, the side heat sink 14 is easily manufactured by extruding. That is, after performing extruding in which a material is extruded in a direction parallel to the fins 14 a, a member obtained by the extruding is cut at regular intervals, and thus the plurality of side heat sinks 14 are obtained. Consequently, the need for additional processing such as cutting work can be reduced. In this regard, as long as the side heat sink 14 has a polygonal shape including the straight line L6 at one side thereof, the heat sink 14 may have a shape different from the above-mentioned parallelogram or trapezoid shape.

As illustrated in FIG. 6, FIG. 8, and FIG. 9, in the front heat sink 12 and the rear heat sink 13, the fins 12 a, 13 a are aligned at regular intervals A. Further, also in the side heat sink 14, the fins 14 a are aligned at the regular intervals A. In addition, the interval A is provided between the fin 14 a-2 situated at the end of the side heat sink 14 and the fin 12 a-1 situated at the end of the front heat sink 12. Further, the interval A is provided also between the fin 14 a-2 and the fin 13 a-1 situated at the end of the rear heat sink 13. With this structure, in the heat sink 11, all of the fins 12 a, 13 a, and 14 a are aligned at the intervals A.

As illustrated in FIG. 7, the heat pipe (heat transfer member in claim 42 for transferring the heat of the integrated circuit 5A to the side heat sink 14 is arranged on the lower surface of the side heat sink 14. In this example, the heat pipe 42 extends from the heat receiving block 41 to the lower side of the side heat sink 14. Specifically, the heat pipe 42 includes a heat receiving portion 42 a which is situated in the heat receiving block 41 and extends in the right-and-left direction, and a heat releasing portion 42 b which extends from the heat receiving portion 42 a in the left direction and is situated under the side heat sink 14. In this example, the heat releasing portion 42 b is curved rearward, and a tip end of the heat releasing portion 42 b is situated under the rear edges 14 c of the fins 14 a. That is, the heat releasing portion 42 b below the side heat sink 14 extends from the front edges 14 b to the rear edges 14 c. The heat receiving portion 42 a receives the heat of the integrated circuit 5A through the heat receiving block 41. Then, the heat is transferred to the side heat sink 14 by the heat releasing portion 42 b.

In this regard, the front heat sink 12 is situated on the heat receiving block 41, as described above. Thus, the integrated circuit 5A is cooled by the front heat sink 12 and the side heat sink 14. As illustrated in FIG. 6, a width in the fore-and-aft direction of each fin 14 a is larger than a width in the fore-and-aft direction of each fin 12 a of the front heat sink 12. Even in a case where the width in the fore-and-aft direction of each fin 12 a of the front heat sink 12 is inevitably reduced in order to avoid interference with other members such as the rear heat sink 13 and the cooling fan 15, it is possible to ensure a sufficient width in the fore-and-aft direction of the side heat sink 14. As a result, it is possible to obtain satisfactory cooling performance.

The side heat sink 14 includes a plurality of fins 14 a-R situated on the right side of the heat releasing portion 42 b, and a plurality of fins 14 a-L situated on the left side of the heat releasing portion 42 b. In other words, the heat releasing portion 42 b is arranged under substantially the center portion in the right-and-left direction of the side heat sink 14. That is, the heat releasing portion 42 b extends from the front edge 14 b of the fin 14 a situated at substantially the center portion in the right-and-left direction thereof, to the rear edge 14 c of the fins 14 a. With this structure, the heat of the heat pipe 42 is diffused over a wide range of the base portion 14 d of the side heat sink 14. Further, as described above, the heat releasing portion 42 b is curved under the side heat sink 14. Thus, the heat of the heat pipe 42 is diffused over a wider range of the base portion 14 d.

Further, a distance D2 between the front edge 14 b of the leftmost fin 14 a-1 and the outer periphery of the cooling fan 15 is larger than a distance D1 between the front edge 14 b of the fin 14 a just above the heat pipe 42 and the outer periphery of the cooling fan 15. By providing the distance D2 larger as described above, it is possible to reduce resistance against rotation of the cooling fan 15 while maintaining cooling performance exerted by the side heat sink 14. That is, when many of the fins 14 a, 12 a are arranged near the cooling fan 15, air resistance against the rotation of the cooling fan 15 occurs. In this example, the distance D2 is large, and hence it is possible to reduce the air resistance. Further, the heat of the heat releasing portion 42 b is most transferred to the fin 14 a situated just above the heat releasing portion 42 b. In this example, the distance D1 is small, and hence a large amount of the air can flow toward the fin 14 a situated just above the heat releasing portion 42 b. As a result, it is possible to improve the cooling performance of the side heat sink 14.

In this regard, in this example, a distance D3 between the front edge 14 b of the rightmost fin 14 a-2 and the outer periphery of the cooling fan 15 is larger than the distance D1. Further, a front edge 14 b of a fin 14 a-3, which becomes tangent to the outer periphery of the cooling fan 15 when the straight line L6 is moved parallel toward the cooling fan 15, is closest to the outer periphery of the cooling fan 15. Further, as the fins 14 a have the larger distances from the fin 14 a-3, the fins 14 a have the larger distances from the outer periphery of the cooling fan 15.

The front heat sink 12, the rear heat sink 13, and the side heat sink 14 are formed by, for example, extruding. Specifically, in a manufacturing step for the heat sinks 12, 13, and 14, extruding is performed, in which a material such as aluminum is extruded in a direction parallel to the fins 12 a, 13 a, and 14 a. After that, a member obtained by the extruding is cut at intervals corresponding to the widths of the front heat sink 12, the rear heat sink 13, and the side heat sink 14. When manufacturing the front heat sink 12 and the rear heat sink 13, the member obtained by the extruding is cut in a plane orthogonal to the extruding direction. When manufacturing the side heat sink 14, the member obtained by the extruding is cut in a plane oblique to the extruding direction (that is, plane including the line L6 along which the front edges 14 b are aligned).

As described above, in the cooling device 10, the fins 14 a of the side heat sink 14 includes, on their sides toward the cooling fan 15, the front edges 14 b. The front edges 14 b are aligned on the oblique line L6 with respect to the direction along the perpendicular lines of the fins 12 a, 13 a, and 14 a. Further, the front edges 14 b are formed on the outer periphery of the cooling fan 15. In other words, the line L6 passes by the outer periphery of the cooling fan 15. With this structure, not only the air flowing from the cooling fan 15 just rearward, but also the air flowing from the cooling fan 15 obliquely rearward can pass through the heat sink 11, and hence it is possible to increase usage efficiency of the air flow.

Further, the heat sink 11 includes the side heat sink 14 and the front heat sink 12. The heat sink 12 is arranged next to the side heat sink 14 and surrounds a part of the outer periphery of the cooling fan 15 together with the side heat sink 14. This structure of the heat sink 11 can farther improve cooling performance of the cooling device.

Further, the front heat sink 12 includes the plurality of fins 12 arranged in parallel to one another and aligned at the intervals. The fins 12 are arranged such that the perpendicular lines thereof is along a direction of the perpendicular lines of the fins 14. According to this structure, the air passing through the side heat sink 14 and the air passing through the front heat sink 12 flow in the same direction. Thus, it is possible to effectively cool a device which is arranged in the same direction from the side heat sink 14 and the front heat sink 12. And, it is possible to smoothly discharge, toward the outside of the electronic device, the air from the side heat sink 14 and the front heat sink 12.

Further, the fins 14 of the side heat sink 14 are aligned at regular intervals A. The fin 14 a-2 situated at the end of the side heat sink 14 and the fin 12 a-1 situated at the end of the front heat sink 12 have an interval therebetween which is same as the intervals between the fins 14. This structure can enable the air to smoothly pass through the side heat sink 14 and the front heat sink 12.

Further, the plurality of fins 12 a of the front heat sink 12 are aligned at regular intervals A. The fin 14 a-2 situated at the end of the side heat sink 14 and the fin 12 a-1 situated at the end of the front heat sink 12 have an interval which is same as the intervals between the fins 12. This structure can enable the air to smoothly pass through the side heat sink 14 and the front heat sink 12.

Further, the line L6 on which the front edges 14 b of the fins 14 a are aligned is a straight line. With this structure, in comparison with a structure where the front edges 14 b of the fins 14 a are aligned on a curved line, manufacture of the heat sink 11 can be facilitated.

Further, the rear edges 14 c opposite to the front edges 14 b of the fins 14 a are aligned on another straight line L10 which extends in a direction along the straight line L6. This structure can enable the following manufacturing process of the side heat sinks 14. An original material of the side heat sinks 14 is extruded in a direction parallel to the fins 14 a. And then, the extruded material is cut at regular intervals, that is, at intervals each corresponding to a width in the front-back direction of side heat sink 14. As a result, it is possible to easily produce a plurality of side heat sink 14 and thus increase production efficiency.

Further, the heat sink 11 includes a base portion 14 d formed into a plate shape, and the fins 14 a are formed to be upright on the base portion 14 d. The fins 14 a and the base portion 14 d are formed integrally with each other by extruding in which a material is extruded in a direction parallel to the fins 14 a. According to this structure, it is possible to increase production efficiency of the heat sink 11.

Further, the heat pipe 42 is disposed below the fins 14 a, for transferring heat of the electronic component 5A on the circuit board 5 to the fins 14 a. One part of the plurality of fins 14 a is situated on one side with respect to the heat pipe 42, and another part of the plurality of fins 14 a is situated on the other side with respect to the heat pipe 42. According to this structure, it is possible to transfer heat of the heat pipe 42 to the whole of the plurality of fins 14 a.

Note that, the present invention is not limited to the above-mentioned cooling device 10, and various modifications can be made. For example, in the above description, the side heat sink 14 is arranged on the left side of the front heat sink 12 and the rear heat sink 13. However, the side heat sink 14 may be arranged on the right side of the front heat sink 12 and the rear heat sink 13. In this case, the front edges 14 b of the fins 14 a of the side heat sink 14 are aligned on a line which extends rightward and forward and passes by the outer periphery of the cooling fan 15.

Further, the cooling device 10 is provided with the two heat sinks 12, 13 in addition to the side heat sink 14. However, the cooling device 10 may be provided with only any one of the front heat sink 12 and the rear heat sink 13.

Further, in place of the front heat sink 12 or the rear heat sink 13, or together with the front heat sink 12 or the rear heat sink 13, a heat sink bilaterally symmetrical with the side heat sink 14 may be provided to the cooling device 10.

Further, in the above description, the front heat sink 12, the side heat sink 14, and the rear heat sink 13 are individual members. However, any two of or all of the front heat sink 12, the side heat sink 14, and the rear heat sink 13 may be formed integrally with each other.

While there have been described what are at present considered to be a certain embodiment of the invention, it will be understood that various modifications may be made thereto, and it is intended that the appended claims cover all such modifications as fall within the true spirit and scope of the invention. 

1. A cooling device, comprising: a heat sink including a plurality of fins formed to be plate shaped and aligned at intervals, the heat sink being arranged such that perpendicular line of any one of the plurality of fins are along a first direction; and a cooling fan situated from the plurality of fins in a second direction perpendicular to the first direction, the cooling fan being rotatable about a center line along a third direction perpendicular to both the first direction and the second direction, wherein: the heat sink includes a plurality of oblique arrangement fins serving as at least one part of the plurality of fins; and the plurality of oblique arrangement fins include edges aligned on an oblique line with respect to the first direction and formed on an outer periphery of the cooling fan.
 2. The cooling device according to claim 1, wherein the heat sink includes a first heat sink provided with the plurality of oblique arrangement fins, and a second heat sink arranged next to the first heat sink and surrounding one part of the outer periphery of the cooling fan together with the first heat sink.
 3. The cooling device according to claim 2, wherein the second heat sink includes the plurality of fins formed to be plate shaped, which are arranged in parallel to one another and aligned at the intervals.
 4. The cooling device according to claim 3, wherein: the plurality of oblique arrangement fins of the first heat sink are aligned at regular intervals; and An oblique arrangement fin situated at an end of the first heat sink and a fin situated at an end of the second heat sink have an interval therebetween which is same as the regular intervals.
 5. The cooling device according to claim 3, wherein: the plurality of fins of the second heat sink are aligned at regular intervals; and An oblique arrangement fin situated at an end of the first heat sink and a fin situated at an end of the second heat sink have an interval therebetween which is same as the regular intervals.
 6. The cooling device according to claim 1, wherein the edges of the plurality of oblique arrangement fins are aligned on a straight line oblique with respect to the first direction and formed on the outer periphery of the cooling fan.
 7. The cooling device according to claim 6, wherein edges opposite to the edges of the plurality of oblique arrangement fins are aligned on another straight line which extends in a direction along the straight line.
 8. The cooling device according to claim 6, wherein: the heat sink includes a base portion formed into a plate shape; the plurality of oblique arrangement fins are formed to be upright on the base portion; and the plurality of oblique arrangement fins and the base portion are formed integrally with each other by extruding in which a material is extruded in a direction parallel to the plurality of oblique arrangement fins.
 9. The cooling device according to claim 1, further comprising a heat transfer member arranged under the plurality of oblique arrangement fins, for transferring heat of an electronic component on a circuit board to the plurality of oblique arrangement fins, wherein one part of the plurality of oblique arrangement fins is situated on one side with respect to the heat transfer member, and another part of a plurality of oblique arrangement fins is situated on the other side with respect to the heat transfer member.
 10. An electronic device, comprising the cooling device according to claim 1 built therein. 